What does 1 Corinthians 10:3 mean?

Paul is making a connection between the experience of the Israelites in the wilderness and the Christians in Corinth. He has written that the Israelites were baptized into Moses through their universal experiences of passing through the Red Sea (Exodus 14:21–28) and being led by the Lord in a pillar of cloud (Exodus 13:21). Christians, too, receive God's guidance and protection, as well as being baptized into Christ, our connection to God.

Now Paul adds that the Israelites all ate the same spiritual food, referring to God's provision of manna from heaven during their years in the wilderness (Exodus 16:4, 15). Christians, including those in Corinth, eat spiritual food from heaven in the sense that we symbolically take in Christ's body and blood through the sacrament of communion (John 6:31–34).